The current use of wound dressing materials is based mostly on empirical knowledge rather than on real scientific understanding of the healing process. A certain number of characteristic properties of materials suitable for wound dressing has been clarified. They are: capacity to facilitate removal of exudates and toxic compounds, capacity to maintain humidity at the interface wound tissue/dressing, capacity to permit gas exchange and thermal insulation, protection against secondary infections, easy removal from the wound without damaging the newly formed tissue.
In the course of the last few years, polysaccharide based materials have been made available for wound treatment and general medications; they possess most of the characteristics indicated above while retaining specific properties. Important commercial products are: cross-linked dextran (Debrisan.RTM., Pharmacia), polyacrylamid agar (Geliperm.RTM., Geistlich), carboxymethyl cellulose (Comfeel.RTM.), hyaluronic acid (Connettivina.RTM., Fidia). Very little is known at the histological level about the effects of these polysaccharide based remedies, whilst the clinical data are abundant and the physico-chemical informations are well known. For no one of these dressings, however, a real biological significance is shown. As far as chitin-based wound dressings are concerned, in Japan one product is commercially available (Beschitin.RTM., Unitika), which is a non-woven fabric manufactured from chitin filaments. So far, no commercial exploitation, has been made of chitosan-based medical items and very limited research has been done in such field.